The present invention relates generally to a concrete finishing, smoothing and/or leveling apparatus and, more particularly, to a concrete smoothing and leveling apparatus which is operable on partially cured concrete to smooth the partially cured concrete surface to a flat, level surface.
There is a growing need in the industry for close-tolerance, flat and level concrete floors for various buildings or structures, such as warehouses, manufacturing facilities and the like. Many manufacturing plants include high-precision equipment which must be level and thus benefit from having close-tolerance floors to allow for easier initial installation, set up and/or reorganization of the equipment. Additionally, high-density warehouse facilities often utilize narrow aisles and high-reach forklifts to reach tall storage racks for shelving. Any offset from level of the floor then corresponds to an offset from vertical of the high-reach forklift, which may result in difficulty in maneuvering the forklifts along the aisles and in reaching the upper shelves. Such warehouse facilities thus also benefit from very smooth and accurately level floors for efficient installation and use of equipment and for stocking of the shelves.
Close-tolerance floors are often referred to in the industry as xe2x80x9csuper-flat floorsxe2x80x9d or simply xe2x80x9csuper flatsxe2x80x9d. Such super-flat floors are typically expensive for concrete contractors to produce, since such projects usually require specialized equipment and experienced personnel with a thorough knowledge of the process. Because of the high cost of the super-flat floors, often only specified areas of a building floor will be made to super-flat specifications, such as within anticipated aisleways of a given floor plan. However, the spacing or location of the aisles then cannot be easily adjusted later, which increases future renovation costs and possibly the future value and usefulness of the facility.
Close-tolerance, super-flat concrete floors are specified, measured and compared in the concrete industry according to concrete floor profile specification variables. One of these variables is for floor flatness xe2x80x9cF-Fxe2x80x9d and another is for floor levelness xe2x80x9cF-Lxe2x80x9d. These two specifications together are generally referred to in the industry as F-numbers. The F-number system offers a repeatable method for measuring floor quality through statistical means known in the art. Concrete floors having F-numbers near or above the range of F-F 80 and F-L 80 are typically regarded as being super-flat concrete floors.
Super-flat concrete floors are much more difficult and expensive to achieve than those conventionally poured. In order to achieve such super-flat floors, construction work site personnel must be highly trained and skilled, and special equipment is often required to place and finish the concrete. Striking-off wet, uncured concrete to a specified grade for a conventional floor can be performed using hand tools. However, a large number of workers are required to finish the floor, and production speed of the floor is thus relatively slow with such conventional processes. Additionally, as an operator continues to work with the manual devices, such as trowels and scrapers, for a long period of time, the operator will tire as the day goes on, which will have an adverse affect on the final F-numbers and quality of the floor. Therefore, because many flat floors are finished by manual labor, the floors are likely to have relatively poor accuracy in the overall surface levelness and flatness.
In many applications, the use of a laser screeding device, such as the Somero Laser Screed, developed by Somero Enterprises of Houghton, Mich., is often required when the goal of a super-flat floor is to be achieved. Other special application tools and equipment, such as highway straight edges, power trowels, pan machines and double trowels, may be used separately, at the same time, or in combination with one another, during the finishing process. Because a significant amount of time and effort of experienced and skilled workers and special equipment and/or machinery is required to achieve a super-flat floor quality, achieving such a floor is often a relatively expensive and time consuming process.
Many concrete processing applications have implemented a spinning tube, or the like, in constructing a concrete floor or surface. However, such spinning tube applications are implemented as an initial strike-off tool or screed for striking-off or screeding freshly placed and uncured concrete to the desired grade. These tube type roller screeds are necessarily supported on some type of preset forms or screed rails to maintain grade height. Because these screeding devices are applicable only to freshly poured, uncured concrete, implementation of such devices does not result in a close-tolerance or super-flat concrete floor surface. The additional manual processes still have to be performed on the surface after the initial screeding operation is completed, and after the concrete is at least partially cured and set up, in order to obtain such a super-flat, high quality, floor surface.
Therefore, there is a need in the art for a concrete smoothing and leveling apparatus which is capable of finishing a concrete surface to a super-flat or close-tolerance finish. The apparatus should require minimal manual labor processes and be inexpensive to operate over the entire floor surface.
The present invention is intended to provide a concrete floor or surface finishing apparatus which is operable to finish a surface of a partially cured concrete slab to a super-flat, smooth and level floor surface. The apparatus of the present invention requires minimal manual labor processes to achieve the desired floor surface quality. Additionally, the apparatus of the present invention is applicable to large floor surface areas, whereby the entire floor surface can achieve the desired super-flat and level floor qualities.
According to a first aspect of the present invention, a concrete finishing apparatus for smoothing and leveling partially cured concrete at a support surface includes a movable unit and at least one rotatable finishing member mounted at the movable unit. The movable unit is movable and supported over and/or on the partially cured concrete and is movable in at least a first direction. The at least one rotatable finishing member is an elongated cylindrical member, such as a cylindrical tube, roller, cylinder or the like. The rotatable finishing member includes a longitudinal axis and is rotatable about the longitudinal axis. The rotatable finishing member defines a cylindrical contact surface therealong which is adapted to contact a surface of the partially cured concrete as the rotatable finishing member is rotated over the partially cured concrete. The finishing member is rotatable such that the contact surface moves relative to the surface of the partially cured concrete as the movable unit and the rotatable finishing member are moved over the partially cured concrete.
Preferably, the rotatable finishing member is positioned behind the movable unit as the movable unit moves in the first direction. The finishing member is rotatable in an opposite direction from the first direction such that the contact surface is movable relative to the partially cured concrete surface in the first direction as the movable unit moves in the first direction.
In one form, the rotatable finishing member is vertically adjustable. Optionally, the concrete finishing apparatus may include a laser leveling system. The rotatable finishing member is then vertically adjustable in response to the laser leveling system. The rotatable finishing member may also or otherwise be variably weighted to adjust or vary an amount of force or downward pressure being applied to the partially cured concrete by the rotatable finishing member.
The movable unit of the concrete finishing apparatus includes at least one support which spreads the weight of the movable unit over an area of the partially cured concrete to limit depression of the partially cured concrete by the movable unit. In one form, the at least one support includes at least four inflatable tires. In another form, the at least one support includes at least two elongated rollers which are rotatable to move the movable unit over the concrete surface. In yet another form, the at least one support includes at least two continuous tracks.
Alternately, the movable unit may include only one tire, wheel or roller, or two generally coaxial tires, wheels or rollers, such that the rotatable finishing member is substantially supported on the partially cured concrete surface due to the weight of the finishing member. Alternately, the movable unit may include an air cushion unit which is operable to be supported above the concrete surface via a cushion of air generated by the air cushion unit. It is further envisioned that the movable unit may be a power trowel or riding trowel apparatus, with the rotatable finishing member mounted at a rearward end of the power trowel, without affecting the scope of the present invention.
The concrete finishing apparatus of the present invention may include two rotatable finishing members positioned at opposite ends of the movable unit. One of the two rotatable finishing members then may be lowered to contact and smooth the partially cured concrete surface when the movable unit is moved in the first direction, while the other of the two rotatable finishing members is lowered to contact and smooth the partially cured concrete surface when the movable unit is moved in a second direction. The second direction is generally opposite the first direction. Optionally, both rotatable finishing members may be lowered to engage and finish the partially cured concrete surface as the movable unit moves over and along the partially cured concrete surface.
The rotatable finishing member of the concrete finishing apparatus may be positioned relative to the movable unit such that the longitudinal axis of the rotatable finishing member is generally normal to the first direction. Alternately, the rotatable finishing member may be positioned relative to the movable unit such that the longitudinal axis of the finishing member is skewed or canted relative to the first direction, i.e., positioned at an angle to the first direction. Preferably, the orientation of the finishing member relative to the movable unit is adjustable in order to change the skew or angle of the rotatable finishing member depending on the application.
According to another aspect of the present invention, a method for finishing a concrete surface of partially cured concrete includes providing a concrete finishing apparatus having a movable support and a rotatable finishing member. The movable support and rotatable finishing member are moved over and/or on the concrete surface such that the movable support is supported on and/or over the partially cured concrete. The rotatable finishing member defines a generally cylindrical contact surface for contacting the concrete surface and is positioned at the concrete surface. The rotatable finishing member is rotated about a longitudinal axis of the finishing member to move the contact surface relative to the partially cured concrete surface as the movable support and the rotatable finishing member move over the concrete surface.
In one form, the method includes moving the movable support and the rotatable finishing member in a first direction. The method may further include rotating the rotatable finishing member to move the contact surface in the first direction. The method may also include positioning the rotatable finishing member behind the movable support as the movable support moves in the first direction.
During operation, the rotatable finishing member is preferably positioned and pulled behind the movable unit as the movable unit moves in the first direction. The rotatable finishing member is then rotatable in a generally opposite direction from the first direction, such that the contact surface is movable relative to the concrete surface in the first direction as the movable unit moves in the first direction. The rotational speed of the finishing member is selected such that the finishing member contact surface generates sufficient slippage over the partially cured concrete to smooth the concrete to a high quality finish.
The movable support may be ridden and driven by an operator, or manually moved over the partially cured concrete surface by an operator walking on the surface, or may be remotely controlled by a remote control device or programmable to move and finish the partially cured concrete surface in a programmed manner.
Therefore, the present invention provides a concrete smoothing and finishing apparatus and method for smoothing partially cured concrete at a support surface to a super-flat, high quality finish. The apparatus is operable to provide a smooth finish over a large area and requires minimal manual processes. Accordingly, the present invention provides a more efficient and effective smoothing and finishing apparatus and method for achieving high quality, super-flat and level floor surfaces. In addition, the machine and process method of the present invention may also serve to significantly shorten the cure cycle time of the finished concrete surface such that in the overall perspective, less time, effort, and cost may be incurred by the construction contractor, while at the same time, improving the overall quality of the finished concrete surface.
These and other objects, advantages, purposes and features of this invention will become apparent upon review of the following specification in conjunction with the drawings.